an organisation founded by Tsar's decree, the Neva Yacht Club's being the world's oldest is challenged by the Royal Cork Yacht Club in Ireland, founded in 1720. Both clubs have gone through periods of dormancy and undergone various name changes. Russian Empire 1720s 1725 Rebar Rebar or reinforcing bar is a common metal bar (typically made of steel), used in reinforced concrete and reinforced masonry structures. Rebar was known in construction well before the era of the modern reinforced concrete, since some 150 years before its invention rebar were used in the Leaning Tower of Nevyansk in Russia, which was built on the orders of the industrialist Akinfiy Demidov between 1725 and 1732. The purpose of such construction is one of the many mysteries of the tower. The cast iron used was of very high quality, and there is no corrosion on them up to this day. 1730s 1732 Cast iron cupola / Lightning rod The cast iron cupola was a type of cupola made of cast iron rather than made from stone or brick as it was in ancient or medieval domes. The first application of this technology is found in the mysterious Leaning Tower of Nevyansk, completed in 1732. The tower's tented roof had a cast iron carcass and outer shell. The second time, this technique was applied only some 100 years later, during the reconstruction of the Mainz Cathedral in Germany in 1826, while the third time it was used in the dome of Saint Isaac's Cathedral in St. Petersburg, built in the 1840s. The very top of the tower was crowned with a gilded metallic sphere with spikes. Since it was grounded through the rebar of the tower carcass, it acted like a lightning rod. Thus, the Russian builders de facto created the first lightning rod in the Western world some 25 years before Benjamin Franklin, however it is not known whether that was intentional. 1733 Peter and Paul Cathedral The Peter and Paul Cathedral is a Russian Orthodox cathedral located in St. Petersburg, Russia. It is the first and oldest landmark in St. Petersburg, built between 1712 and 1733 inside the Peter and Paul Fortress. Both the cathedral and the fortress were originally built under Peter the Great and designed by Domenico Trezzini. The cathedral is the burial place of all Russian Emperors from Peter I to Nicholas II, with the exception of Peter II.